We study the m = 3 bootstrap percolation model on a cubic lattice, using Monte Carlo simulation and finite-size scaling techniques. In bootstrap percolation, sites on a lattice are considered occupied (present) or vacant (absent) with probability p or 1 − p, respectively. Occupied sites with less than m occupied first-neighbours are then rendered unoccupied; this culling process is repeated until a stable configuration is reached. We evaluate the percolation critical probability, pc, and both scaling powers, yp and y h , and, contrarily to previous calculations, our results indicate that the model belongs to the same universality class as usual percolation (i.e., m = 0). The critical spanning probability, R(pc), is also numerically studied, for systems with linear sizes ranging from L = 32 up to L = 480: the value we found, R(pc) = 0.270 ± 0.005, is the same as for usual percolation with free boundary conditions.